the meaning of プラーク

[keannu2]

Hi, everyone! Nice to meet all of you!
I joined this website to learn Japanese today. Please help me a lot!
よろしくお願いします！
In the attached file's No 5, the correct answer is プラーク
Could anyone let me know the meaning of this word?
Thank you in advance!

 

[Toritoribe]

Not プラーク (pura-ku), but プルーフ (puru-fu), i.e., "proof".

 

[keannu2]

Sorry, I was mistaken. Thank you very much!

 

[Toritoribe]

No need to apologize. Welcome to JREF!